How to build an Ubuntu/Debian SD image from scratch


#1

I tried to build an Ubuntu/Debian image from scratch (i.e. not using any of the pre-compiled images). It’s working now, and maybe someone finds it useful. This is what i did, step by step:

I’m using the kernel 4.14, from the official github repository. You have to use a PC running Ubuntu 16.04 (64 Bit). Ubuntu 18.04 will not work correctly because of the gcc version!

To download and compile the kernel:

1. Install tools required tools:

apt-get install git build-essential automake autoconf gcc-arm-linux-gnueabihf u-boot-tools libc6-armhf-cross bc libc6-dev libncurses5-dev libssl-dev bison flex pv

2. If your gcc is newer than version 5 (check with arm-linux-gnueabihf-gcc), install gcc 5:

apt-get install gcc-5-arm-linux-gnueabihf

update-alternatives --install /usr/bin/arm-linux-gnueabihf-gcc arm-linux-gnueabihf-gcc /usr/bin/arm-linux-gnueabihf-gcc-7  50

update-alternatives --install /usr/bin/arm-linux-gnueabihf-gcc arm-linux-gnueabihf-gcc /usr/bin/arm-linux-gnueabihf-gcc-5  100

update-alternatives --config arm-linux-gnueabihf-gcc

3. Clone BSP for kernel 4.14 into a subdirectory bsp14:

git clone https://github.com/BPI-SINOVOIP/BPI-R2-bsp-4.14.git bsp14

4. Build kernel 4.14 and bootloader (select “1”):

cd bsp14

./build.sh

cd ..

Now create the image:

1. Install required tools:

apt-get install qemu-user-static debootstrap binfmt-support parted zip

2. Create image file (8GB):

dd if=/dev/zero bs=1M count=7296 | pv | dd of=bpir2.img

3. Load image as virtual drive:

losetup /dev/loop8 bpir2.img

4. Make partitions and format:

parted -s /dev/loop8 mklabel msdos

parted -s /dev/loop8 unit MiB mkpart primary fat32 -- 100MiB 356MiB

parted -s /dev/loop8 unit MiB mkpart primary ext2 -- 356MiB 7295MiB

partprobe /dev/loop8

mkfs.vfat /dev/loop8p1 -I -n BPI-BOOT

mkfs.ext4 -O ^has_journal -E stride=2,stripe-width=1024 -b 4096 /dev/loop8p2 -L BPI-ROOT

sync

parted -s /dev/loop8 print

The last step should show 2 partitions (one FAT and one EXT). Hint: the parted software prints the start offsets and lengths in MB (1000-based) and not in MiB (1024 based), so the start offset 105MB is correct.

Now fill the linux root filesystem:

1. Mount filesystems:

mkdir /mnt/rootfs

mount /dev/loop8p2 /mnt/rootfs

mkdir /mnt/rootfs/boot

mount /dev/loop8p1 /mnt/rootfs/boot

2. Bootstrap ubuntu rootfs (part 1):

debootstrap --arch=armhf --foreign xenial /mnt/rootfs

cp /usr/bin/qemu-arm-static /mnt/rootfs/usr/bin/

3. Continue bootstrapping (part 2) in the chroot:

chroot /mnt/rootfs

export LANG=C

/debootstrap/debootstrap --second-stage

4. Set apt packages 16.04 and update/upgrade (still in chroot):

echo "" > /etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial main restricted">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial main restricted">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial universe">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial universe">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial multiverse">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial multiverse">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial-updates main restricted">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial-updates main restricted">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial-updates universe">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial-updates universe">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial-security main restricted">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial-security main restricted">>/etc/apt/sources.list

echo "deb http://ports.ubuntu.com/ubuntu-ports/ xenial-security multiverse">>/etc/apt/sources.list

echo "deb-src http://ports.ubuntu.com/ubuntu-ports/ xenial-security multiverse">>/etc/apt/sources.list

apt-get update

apt-get upgrade

apt-get dist-upgrade

5. Install packages (still in chroot), add more packages as you need:

apt-get install sudo nano openssh-server locales ntpdate htop pv

6. Set hostname (still in chroot):

echo "bpi-r2" >/etc/hostname

nano /etc/hosts

-> add "bpi-r2" to line with 127.0.0.1

7. Set root password (still in chroot), if you want to enable root login:

passwd

8. Create one or more users (still in chroot):

useradd -m -G users,sudo,ssh -s /bin/bash bpi

passwd bpi

9. Configure locales (still in chroot), add the locales that you need:

locale-gen en_US

locale-gen en_US.UTF-8

dpkg-reconfigure locales

dpkg-reconfigure tzdata

update-locale LANG=en_US.UTF-8

10. Configure fstab (still in chroot):

nano /etc/fstab
->

proc /proc proc defaults 0 0

LABEL=BPI-BOOT /boot vfat errors=remount-ro 0 1

LABEL=BPI-ROOT / ext4 defaults,noatime 0 0

11. Configure network 16.04 (still in chroot), update for your requirements: nano /etc/network/interfaces

->

auto lo

iface lo inet loopback

auto eth0

iface eth0 inet manual

auto wan

iface wan inet dhcp

auto lan0

iface lan0 inet static

address 192.168.1.1

netmask 255.255.255.0

#gateway 192.168.0.1

auto lan1

iface lan1 inet static

address 192.168.1.2

netmask 255.255.255.0

#gateway 192.168.0.1

auto lan3

iface lan3 inet static

address 192.168.1.3

netmask 255.255.255.0

#gateway 192.168.0.1

auto lan4

iface lan4 inet static

address 192.168.1.4

netmask 255.255.255.0

#gateway 192.168.0.1

12. Configure sshd (still in chroot), i prefer using Pubkey-auth only and disable password auth:

mkdir /root/.ssh

chmod 0700 /root/.ssh

touch /root/.ssh/authorized_keys

chmod 0600 /root/.ssh/authorized_keys

nano /etc/ssh/sshd_config

->

PubkeyAuthentication yes

PasswordAuthentication no

Your public key must be appended to /root/.ssh/authorized_keys.

20. Exit and remove qemu:

exit 

rm /mnt/rootfs/usr/bin/qemu-arm-static

Now write the image file:

1. Copy boot partition files:

tar -x -f bsp14/SD/BPI-BOOT-bpi-r2.tgz --keep-directory-symlink -C /mnt/rootfs/boot

2. Copy kernel files to root file system:

tar -x -f bsp14/SD/4.14.34-BPI-R2-Kernel.tgz --keep-directory-symlink -C /mnt/rootfs

tar -x -f bsp14/SD/4.14.34-BPI-R2-Kernel-net.tgz --keep-directory-symlink -C /mnt/rootfs

3. Copy bootloader files to root file system:

tar -x -f bsp14/SD/BOOTLOADER-bpi-r2.tgz --keep-directory-symlink -C /mnt/rootfs

4. Blacklist power button module:

echo "blacklist mtk_pmic_keys" > /mnt/rootfs/etc/modules-load.d/mtk_pmic_keys.conf

5. Unmount:

umount /mnt/rootfs/boot

umount /mnt/rootfs

6. Write header blocks (get these files from the BPI-files repository on github):

gunzip -c BPI-R2-HEAD440-0k.img.gz | dd of=/dev/loop8 bs=1024 seek=0

gunzip -c BPI-R2-HEAD1-512b.img.gz | dd of=/dev/loop8 bs=512 seek=1

7. Write preloader and u-boot bootloader:

dd if=bsp14/mt-pack/mtk/bpi-r2/bin/preloader_iotg7623Np1_sd_1600M.bin of=/dev/loop8 bs=1024 seek=2

dd if=bsp14/u-boot-mt/u-boot.bin of=/dev/loop8 bs=1024 seek=320

sync

8. Remove loop device:

losetup -d /dev/loop8

9. Zip image (optional):

zip bpir2.img.zip bpir2.img

Now it’s finished. Write the image file to a 8GB SD card (e.g. with the Etcher tool, or simply with dd), put it in your BPI-R2 and power on.

Only the debug UART is used (no HDMI), so connect a USB serial adapter to the 3-pin debug header and start a terminal like minicom.


#2

One important hint: the u-boot bootloader will not work if compiled with gcc 5.5.0 or greater! It only works with gcc 5.4.0

WIth gcc 5.5, the u-boot.bin is smaller and there are some entries in the jump/pointer table at the end missing, so that it cannot be started by the preloader.

This took me about 2 days to figure out … :confused:


(Frank W.) #3

you know my wiki and my repos? Most information was already there…in uboot-repo there is a hint it cannot be compiled with gcc5

There are also some other problems like ubuntu 18.4 uses netplan by default so config via interfaces-file is not possible till fallback to ifupdown


#4

yes, i know your wiki. There is a lot of helpful information, thanks for that.

The informations for building an image from the scratch are a little bit “scattered”, imho, so i think it could be helpful to have all detailed informations about this topic in one single post.

I also found that the default build scripts in the official repository always create an image with the u-boot and a pre-loader programming the DRAM to 1333MHz, but there is also an unused pre-loader for the 1600MHz DRAM. I tried the 1600 version and it’s working fine, at least with my board (I don’t know if the kernel re-programs the DRAM speed later; in this case, the preloader version doesn’t matter).

One information is not in your wiki afaik: the problem with the u-boot building with gcc 5.5. If building with gcc 5.5, the pre-loader runs, but the board crashes when u-boot should be started. Do you have any clue why gcc5.5 cannot compile the bootloader correcly?

Ubuntu 18.04 is working as well. Did you try to use netplan for interface configuration? I think it should also work similar to the “old” interface version (the yaml config file has another format, of course). I’'l try that next.


(Frank W.) #5

I have no clue why this is happen

but i’ve added info here: https://github.com/frank-w/bpi-r2-uboot/blob/master/README.md

(I don’t know if i tried all gcc versions but also spend some time to it)

First mentioned here: How to extend the uboot-menu found no difference in build.log which causes this problem

But please do not spend to much time in uboot…some people working on mainline-support.

For netplan i did not found out how to bring eth0/eth1 up.

Btw. You use official 4.14…imho it is lacking some features and is older.


#6

Thanks for the info. Btw: u-boot is also working with gcc 5.4, but not with gcc 5.5

I don’t spend more time in the bootloader thing. I’m just happy that it’s working now :slight_smile:

It was just important for me to build a system from the scratch so that I can configure/install only the software that I need. For my project, I just need the UART1, GPIO, USB and network interfaces of the board (and several software packages :wink:). This seems to work for me.

I’ll try your updated 4.14 kernel repository now.


(Frank W.) #7

thank you for the info, i’ve updated my bug-report on it: https://bugs.linaro.org/show_bug.cgi?id=3917 will update my uboot-repo also when i’m at home

as far i can see you create also the partitions and boot-block from scratch (i used that from existing image)…i will try to do this my own :wink: thanks for that

seems you overwrite it in step 6 (don’t know how bug the images are, but these are in the first 1M):

  1. Write header blocks (get these files from the BPI-files repository on github):

    gunzip -c BPI-R2-HEAD440-0k.img.gz | dd of=/dev/loop8 bs=1024 seek=0

    gunzip -c BPI-R2-HEAD1-512b.img.gz | dd of=/dev/loop8 bs=512 seek=1

btw. your network-config seems wrong (all lan-ports with same subnet but different addresses)…i can’t imagine that this works :hushed: this block also has broken formatting…and i suggest also a clean-up after installing the packages (apt-get clean + dd if=/dev/zero of=rootfs/file.dat;rm file.dat) to mae the image file smaller after packing


#8

I checked these 2 images with a hex editor: the first is the header with the SDMMC_BOOT signature and the pointer to the 2nd header (0x00000200). It’s exactly 440 bytes long and obviously intended to overwrite the code section in the master boot record created with parted, but not the partition table (which is located at the end of the 512 byte MBR. after the 440 bytes).

The second image is the 2nd header with the signature BRLYT and the pointer to the preloader address (0x00000800), and some other values (i don’t know the meaning).

yes, it’s not working that way :wink:

ok, thx, good hint.


(Frank W.) #9

have separated the basic SD-Setup from the OS-Part and added to my wiki: https://www.fw-web.de/dokuwiki/doku.php?id=en:bpi-r2:storage#sd-card


#10

Perfect, thx.

Btw: I tried the updated 4.14 kernel from your repository with Ubuntu 18.04. Works like a charm :smiley: I also added the bonding driver, that i need for my project (compiling is disabled by default).


(Frank W.) #11

If you have a working config please post it. I can also add bonding-driver as module


#12

I just activated the compiling of the bonding driver as module.

To start the bonding, it’s required to load the module, either with modprobe or by adding it to a modules config, e.g. in /etc/modules-load.d/bonding.conf.

Also, the command echo +bond0 > /sys/class/net/bonding_masters must be executed to create the bonding device bond0.


(Frank W.) #13

I mean the complete configuration with definition of bonding ports.

Btw. In gcc-bug-report a bisect is requested. Can you try this?